Feast or famine: The diet that won't just help you lose weight, you'll live longer and be brainier!

As all dieters will know, there is nothing more tedious than counting calories or weighing foods for a meal plan. Especially if you then don't lose weight. But there's now an effective weight-loss regimen that is not only simple, it promises significant health benefits - from easing asthma symptoms and reducing blood sugar levels, to fending off heart disease and breast cancer and protecting brain cells. Apparently, you'll also live longer.

The diet goes under various names - The Alternate-Day Diet, Intermittent Fasting or The Longevity Diet - but the principle is the same: eat very little one day (50 per cent of your normal intake) and as much as you like the next. This appears to trigger a 'skinny' gene that encourages the body to burn fat.

Researchers first discovered the benefits of low-calorie eating in the Thirties. They found that putting a rat - or a worm, or a fruit fly or just about any animal, as it turned out - on a permanent very low calorie diet helped the animal live about 30 per cent longer than normal. The animal had clearer arteries, lower levels of inflammation, better blood sugar control and its brain cells were less likely to get damaged. Meanwhile, rates of diseases linked to ageing all dropped. But while scientists have known for years that animals on a low-calorie diet were healthier, no human - except a few iron-willed fanatics - could permanently stick to this regime.

The big breakthrough came in 2003 when Dr Mark Mattson, an American neuroscientist, discovered rats still enjoyed all those health benefits even when their calories were cut only on alternate days.